[dm-crypt] Detached headers, multiple drives and UUIDs

7heo 7heo at mail.com
Mon Apr 10 23:45:52 CEST 2017


On Mon Apr 10 23:29:20 2017 GMT+0200, Robert Nichols wrote:
> On 04/10/2017 03:53 PM, 7heo wrote:
> > On Mon Apr 10 21:10:51 2017 GMT+0200, Milan Broz wrote:
> 
> >> And the activated device-mapper UUID is something else - it is constructed
> >> as LUKS prefix plus LUKS header UUID plus activated name (then cannot
> >> be the same).
> >
> > Then I have to try to fetch the device mapper again, because that was what caused all this. I assumed that the device-mapper UUID was directly derivated from the LUKS UUID.
> 
> The UUID reported by "blkid" and "lsblk -f" is _exactly_ the luksUUID. The UUID reported by "dmsetup info" is the luksUUID prefixed by "CRYPT-LUKS1-" and suffixed by "-{mapper_name}". If you leave the UUID the same, the output from "blkid" and "lsblk -f" will be confusing.

Correct me if I'm wrong, but that could be a problem for some scripts, couldn't it?

Theo.


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